T‐cell papulosis associated with B‐cell malignancy: a distinctive clinicopathologic entity

Abstract

We propose the denomination 'T-cell papulosis associated with B-cell malignancy' (TCP-BCM) for this distinctive eruption. Although resulting in various histopathological pictures, it can be easily recognized by clinicians and may be identified by informed pathologists relying on some key features. An extravasation of tumour B cells with skin-homing properties associated with a secondary, predominant, T-cell immune reaction could explain the clinicopathologic aspect and the prolonged regressive and recurrent course of the disease.

Eosinophilic dermatosis of hematologic malignancy: Correlation of molecular characteristics of skin lesions and extracutaneous manifestations of hematologic malignancy

“…In light of our results and other recent findings, the definition of ED as a nonspecific reaction pattern must be questioned. Mitteldorf et al were the first who identified CLL‐cells in skin specimens of an ED patient using IgH‐PCR and FISH analysis and speculated on a pathogenic role of leukemic cells in ED.…”

“…As observed in our cases, diagnosis of underlying hematologic disease usually precedes the onset of ED and accurate diagnosis of ED is commonly delayed by months resulting in impaired quality of life . Recently, Visseaux et al have proposed a new denomination of ED as “T‐cell papulosis associated with B‐cell malignancy” (TCB‐BCM). This term eliminates the reference to eosinophilic infiltration as a hallmark of the diagnostic criteria established by Byrd et al Interestingly, the authors included about 25% of patients where eosinophils were absent and thus diagnosis of ED would have been missed by the established histological diagnostic criteria .…”

“…Recently, Visseaux et al have proposed a new denomination of ED as “T‐cell papulosis associated with B‐cell malignancy” (TCB‐BCM). This term eliminates the reference to eosinophilic infiltration as a hallmark of the diagnostic criteria established by Byrd et al Interestingly, the authors included about 25% of patients where eosinophils were absent and thus diagnosis of ED would have been missed by the established histological diagnostic criteria . To evaluate whether these cases of TCB‐BCM without eosinophils can be included in one category with cases with eosinophils, it is necessary to investigate if neoplastic B‐cells can be detected in a similar proportion of these cases as in the classic ED cases.…”

“…B‐lymphocytes are usually admixed with a variable amount ranging from 0% to 70% . Using morphological features and appropriate immunohistochemical stainings, clusters of tumor B‐cells have been detected in 47% of biopsy samples by Visseaux and coworkers. Mitteldorf et al also found CD20+ B‐lymphocytes with coexpression of CD5 and CD23, the characteristic phenotype of CLL‐cells.…”

“…Earlier studies used different methods (Southern blot analysis or IgH‐polymerase chain reaction [PCR]) to detect neoplastic cells in the infiltrate and found monoclonal B‐cell populations indicating malignant infiltrates in various amounts (Table ) . In 2018, the French Study Group on Cutaneous Lymphomas added another 37 patients with ED . In a subset of reported patients, the authors compared the molecular data of skin specimens with the molecular data of the same patients' peripheral blood samples and found monoclonal IgH rearrangements in 71.4% of patients (Table ), which were identical to the neoplastic clone in the blood in 92.1% of cases …”